Errors & Limits

Rate limits & quotas

Every request is admitted against your plan's limits. Responses carry x-ratelimit-* headers so you can back off proactively.

Plan	Concurrent streams	Requests / min	Monthly characters
Free	2	30	10,000
Starter	3	60	250,000
Pro	10	300	2,000,000
Scale	15	600	10,000,000

Error semantics

Status	Code	Meaning
`401`	`invalid_api_key`	Missing or invalid key.
`429`	`too_many_requests`	Requests-per-minute exceeded. Retry after `retry-after`.
`429`	`too_many_concurrent_requests`	Concurrent-stream cap reached.
`429`	`insufficient_quota`	Monthly character quota exhausted.
`5xx`	`internal_error`	Transient server error — retry with backoff.

Handling 429

import time, httpx
 
def synth(payload, key):
    while True:
        r = httpx.post(URL, json=payload, headers={"Authorization": f"Bearer {key}"})
        if r.status_code == 429:
            time.sleep(int(r.headers.get("retry-after", "1")))
            continue
        r.raise_for_status()
        return r.content

Streaming